It's relatively easy to generate that amount, especially when you can easily import 20% of your power(very dirty coal power), and also run gas turbines for another 40%, like it is at this very moment https://app.electricitymaps.com/zone/AU-SA
When you're talking about changing the US, it couldn't just import 100GW, Canada and Mexico couldn't provide that much, even if they were clean energy. There is just a difference between providing for one small region vs a continent. Also, Uruguay has huge neighbors, they could easily import-export clean energy from them (they are all hydro-centric).
But yeah, I will see the US going to 70% pretty soon, considering where panel prices are. The one big thing missing is the low cost to install on rooftops. In the US is costs at least 3 dollars per watt to install panels, whereas in the Eu or Australia it's under 1 dollar. The panels themselves can be bought for 15-20 *cents* per watt, so there is a lot of room for improvement. Rooftop solar in the US is a big scam at the moment, they are fleecing the consumers. On the other hand, utility size in the US is cheap, so they will cover the gap.
I am talking for hours when there isn't much renewables. If you set the timeline to 24 hours and look at the hours, you have periods with 55% gas and also 20% imports. You can assume imports are dirty coal, because that is most of Australia.
I've seen others point out that it's the average that matters for emissions and that was what the other commenter was posting. That makes sense to me, the peak usage only matters for cost reasons, and apparently gas turbines are really cheap.
When you're talking about changing the US, it couldn't just import 100GW, Canada and Mexico couldn't provide that much, even if they were clean energy. There is just a difference between providing for one small region vs a continent. Also, Uruguay has huge neighbors, they could easily import-export clean energy from them (they are all hydro-centric).
But yeah, I will see the US going to 70% pretty soon, considering where panel prices are. The one big thing missing is the low cost to install on rooftops. In the US is costs at least 3 dollars per watt to install panels, whereas in the Eu or Australia it's under 1 dollar. The panels themselves can be bought for 15-20 *cents* per watt, so there is a lot of room for improvement. Rooftop solar in the US is a big scam at the moment, they are fleecing the consumers. On the other hand, utility size in the US is cheap, so they will cover the gap.